To add and subtract numbers always begin counting from zero.
When dealing with positive numbers count to the right.
When dealing with negative numbers count to the left.
Calculate 4 - 5 - 3
Imagine moving up and down a number line to get to the answer.
Starting from zero, count up to 4. Then subtract 5. Then subtract 3. The answer is -4.
Calculate: - 2 + 9 - 10 + 6
If you wrote the answer 3 or +3, then well done!
When adding or subtracting negative numbers, remember that when two signs appear next to each other and are different, then you subtract. When two signs are next to each other and they are the same, you add:
Calculate:
a) 10 + - 7
b) 4 - - 3
a) 10 + - 7 = 10 - 7 = 3
b) 4 - -3 = 4 + 3 = 7
Activity
Feeling positive about negative numbers? Test your knowledge with this activity.
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